IADR Abstract Archives
Bonding Effectiveness of Adhesives to Unprepared Erosively Altered Dentin
Objectives: To investigate the bonding performance of different adhesives to unprepared erosively altered dentin.
Methods: Dentin samples underwent an erosive pH-cycling for eight days (6x5min demineralization/ 6x3.5h remineralization per day) or were left untreated as control, respectively. Four different adhesives (Optibond FL [O-Fl]), ExciTE [EX], Clearfil SE Bond [C-SE], G-Bond [GB]) were applied. Microtensile bond strength was measured after 24h water storage (ws) or additional 1h of immersion in 10% NaOCl (bond ageing procedure). Fracture analysis was performed using light microscopy and SEM.
Results:
Table: Microtensile bond strength (MTBS) in MPa.
adhesive
|
| erosion
| non-erosion (control)
| ||||
storage
| n
| ptf
| MTBS
| n
| ptf
| MTBS
| |
Optibond FL
| water
| 28
| 1
| 8.7(±6.2)e,f | 31
| 0
| 41.2(±11.4)a |
NaOCl
| 28
| 4
| 4.7(±3.4)e,f | 23
| 0
| 27.7(±14.9)a,b,c | |
ExiTE
| water
| 29
| 7
| 4.7(±5.4)e,f | 31
| 0
| 30.5(±15.4)a,b |
NaOCl
| 28
| 10
| 1.2(±2.0)f | 30
| 0
| 17.6(±11.8)c,d,e | |
Clearfil SE Bond
| water
| 30
| 0
| 22.5(±18.1)b,c,d | 29
| 0
| 33.1(±11.6)a,b |
NaOCl
| 30
| 1
| 5.3(±3.5)e,f | 30
| 0
| 16.6(±10.9)c,d,e | |
G-Bond
| water
| 29
| 7
| 10.3(±10.7)d,e,f | 30
| 0
| 24.7(±13.8)b,c |
NaOCl
| 27
| 13
| 1.9(±2.9)f | 30
| 0
| 6.0(±4.0)e,f | |
n: number of specimens; ptf: pre-testing failures; Groups with the same superscript are not statistically significant different with ANOVA and Scheffe test (p>0.05).
Evaluated fracture type in the eroded subgroup was 'adhesive', except for C-SE (ws) (cohesive failure in bonding/composite). For the non-eroded samples, 'cohesive' failures were most frequent in O-Fl, EX (ws), C-SE (ws) and GB (ws), whereas adhesive failure was predominant after NaOCl in EX, C-SE and GB. Following SEM, storage in NaOCl highly affected the demineralized interface.
Conclusions: Erosion affected less the bond strength of 'mild' self-etch adhesives than of etch-and-rinse adhesives. Accelerated artificial ageing reduced bond strength in all samples but was most prominent for the one-step adhesive.